Glycemic Index and Appetite Response of Iron-Biofortified Cowpeas (Vigna unguiculata (l.) Walp.) in Healthy Adults and Its Effects on Inflammation and Oxidative Stress in Raw 264.7 Cells.

Abstract

Objective: This study aimed to determine the glycemic index of conventional and biofortified cowpeas, their effects on healthy individuals' appetite, and their anti-inflammatory and antioxidant effects in RAW 264.7 cells.

Methods: Iron biofortified (BRS Aracê, BRS Tumucumaque, and BRS Xiquexique) and conventional (BRS Pajeú) cowpeas were cooked and their chemical composition was analyzed. Eutrophic adults (n = 11) consumed each cowpea and control glucose and post-prandial glucose and appetite responses were obtained over 120 min. In vitro, the study used RAW 264.7 cells stimulated with lipopolysaccharide-LPS (1 µML) and treated with digested cowpea beans (1 mg/mL). Total antioxidant capacity (TAC), nitric oxide, superoxide dismutase (SOD), TNF-α, and IL-10 were analyzed in the cell and culture medium, and NF-κB by immunohistochemistry. The data were analyzed by ANOVA and post-hoc of Tukey (p < 0.05).

Results: All cowpeas had a lower incremental area under the glycemic curve (iAUC) than glucose. In appetite responses, Pajeú had the lowest "hunger sensation" and higher "satiety sensation" (p < 0.05). In vitro analysis showed that Pajeú and Tumucumaque improved TAC and biofortified cowpeas reduced the activation and translocation of NF-κB to nuclei. However, the cowpeas had no effects on SOD activity, nitric oxide, TNF-α, and IL-10 released and production into cells (p > 0.05).

Conclusions: Cowpea, biofortified or not, presents benefits in reducing the glycemic index, but has a moderate impact on induced inflammation, being a sustainable option for human intake and health.

Clinical trial registration: Brazilian Clinical Trials Registry (ReBEC), number RBR-7ntftdv.